It really matters little how Sweden regulates the lower receiver, In the US it is considered a firearm. The export of firearms is regulated. The average gun shop does not have the ability to navigate the red tape needed to obtain the export permission. The additional fees you must pay will all but negate the cost savings.
Shipping a receiver w/o the proper permits will likely create prison time on both ends of the transaction.
Making inquiries into illegal behavior is frowned upon. There is good reason to believe such inquiries are part of a government attempt to pursue charges against an unknowing, but well meaning person trying to be helpful.
The other possiblity is you are sympathetic with an anti gun group here or abroad or a journalist looking for a story.
In any case, this thread is now closed.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball